It is known that armored vehicles or battle tanks with an unmanned turret may have a system for accessing the turret situated between the vehicle and the turret.
There are at least four types of primary needs relative to access to the turret, i.e., the respective needs:                for operational reasons, such as loading ammunition, access to the travel lock (which locks the turret during transport), to the radio, etc.        for maintenance reasons;        for backup reasons during a mission (or manual or degraded operation in case of power failure);        for safety reasons, in particular to provide for the evacuation of the crew of the vehicle via the turret.        
Currently, either the turret is not accessible from the vehicle, or there is still access, generally via a pivoting hatch, for example mounted on hinges, which inevitably opens either toward the outside of the vehicle body, i.e., toward the turret, thus creating a bulk in the inner volume thereof that hinders access to the equipment located in the turret, or toward the inside of the vehicle body, which imposes an intrusion into that body.
Patent BE 633101 A discloses an unmanned turret, capable of rotating relative to its vertical axis, with an automatic-weapon carriage and an unmanned dome capable of receiving gunners, ammunition, etc. and which has an opening that can be closed by a flap, i.e., a hatch for communication with the dome.
Patent EP 844 455 B1 discloses an armored combat vehicle, in which an unoccupied turret is arranged on the upper face of the vehicle body, by means of a rotating ring arranged in the roof plate of the vehicle, with the particularity that the turret does not enter the vehicle body and is capable of housing an automatic large-caliber cannon of up to 50 mm.
Patent EP 1 061 323 B1 discloses an armored transport motor vehicle, characterized in that the gun carriage is formed by an unmanned flat gun-port turret and in that the gun carriage and the automatic onboard weapon are made so as to be able to be remotely controlled from inside the vehicle, the electricity and the electrical signals necessary for the remote control being transmitted to the turret by means of a collecting ring (called “the slipring”). The turret does not enter the vehicle, with the exception of part of the slipring. The turret can rotate relative to the vehicle owing to a circumferential rolling bearing. In the turret are located the base components such as the automatic cannon, the ammunition magazine, the cabling, the machine gun, the strip collector, the lenses, etc. No communication hatch between the vehicle and the turret is expressly provided.
U.S. Pat. No. 3,566,742 A discloses an armored transport vehicle, characterized in that it has an opening on the metal sheet of the roof, capable of adapting several types of weaponry via an interface plate designed based on needs. One of the possibilities of this invention is to be able to install, on the vehicle, an unmanned turret with an automatic cannon and a machine gun via an interface plate that completely closes the base of the turret (without introducing the turret into the vehicle). The patent suggests that, in that interface plate, two access hatches can be installed, i.e., pivoting hatches fastened by hinges.
Patent EP 1 508 765 B1 discloses a modular weaponry station intended to be placed on a combat vehicle, containing a primary weapon and a secondary weapon, which are controlled from outside the station, that is to say that they are remotely operated. The turret rotates relative to the vertical axis using a live ring and is mounted on the metal sheet of the roof of the vehicle. The passage between the vehicle and the station is ensured by an access hatch.
Document WO 2012/063235 A1 discloses a turret assembly, without platform penetration, to reduce the exposure of combatants to enemy forces when the latter access above the platform equipment, comprising:                a base plate on which is mounted at least one piece of fireable and remotely operable interfaceable combatant equipment, the base plate being able to rotate around a substantially vertical axis and supported for rotation by a bearing means mounted inside a platform of a military facility;        a pivoting hatch connected to the base plate, to normally cover a hatch arranged in said base plate and to expose the hatch when the plate is moved; and        a rotatable disc of a slipring unit carried by the hatch, by which electricity to actuate the equipment mounted on top of the platform and to initiate control signals is transmitted to the equipment.        
Patent EP 2 354 749 B1 proposes a solution in the form of intrusion means via the vehicle, which do not cover a large surface area. A base of the turret is mounted rotating on the armored cockpit of the vehicle, via a circumferential fifth wheel. This patent discloses the presence of a rectangular armored hatch between the turret and the cockpit of the vehicle in order to allow communication between both areas. In that case, the hatch opens downwardly. It is mounted pivoting on the base of the turret via a pair of opposed hinges.
This system has the following drawbacks:                its shape: rectangular with smaller dimensions, which limits the passage and makes it difficult;        its position: at the back of the turret, which only allows access to the ammunition magazine and not to the cannon;        the intrusion in the vehicle: compliance with the standard, but does not allow any movement and only allows individual visit. The hatch, opened toward the inside of the vehicle, does not ensure the safety of the crew if the turret is rotated (in manual or electric mode), and does not make it possible to rotate the turret in manual mode in the opening position of the hatch;        when the hatch is closed, the handle is inside the cockpit of the vehicle;        the presence of hinges: constitutes a possible danger, since from a safety perspective for the crew, the intrusion of the handle on the vehicle side may cause accidents with respect to the crew and the hinges may also constitute a danger upon explosion of a mine that could turn the hatch or its components into a threatening projectile;        access to the turret: it does not meet operational ergonomic needs. In light of the position, shape and size of the hatch, it is not possible to access the cannon easily during an ammunition blockage.        
The other hatches typically found in the state of the art (see in particular the documents cited above) have the same shape, are often square or rectangular and always mounted pivoting on hinges and with smaller dimensions for the passage of a person, which is therefore limited to a well-defined position of the body.
Document WO 2012/063235 A1 discloses a turret assembly in a combat vehicle having a rotating base plate on which a piece of remotely-controlled firing equipment is mounted, said base plate comprising a communication hatch with the vehicle. Different hatch systems are described: pivoting vertically with hinges or horizontally with pivot, with an opening parallel to the hatch.
Document EP 2 157 395 A2 discloses an additional hatch-covering system on a combat vehicle in order to ensure the protection of persons against jamming in the hatch when the latter closes electrically. This covering device comprises a certain number of elements or sectors moving relative to one another. In the open position, these elements are positioned above one another and to obtain the closed position, they are moved relative to one another such that each one covers part of the opening of the hatch. This principle is in particular illustrated by the case of sickle-shaped sectors that slide on one another around a pivot with a vertical axis, the sectors being connected to one another by a slot and lug coupling system. This type of light and fragile covering system is not intended to replace the armor or sealing plate of the hatch, but rather the rolling blind or flap for additional protection used thus far. It is only when the additional protection flap or system is completely deployed in the closing position that the electric closing system for the armored hatch is activated, completely safely for the occupants of the armored vehicle.